It is played using harmonics, with the string's tension varied by the use of a flexible rod manipulated with the left hand.
For the human voice see Overtone singing, which uses harmonics.
Using harmonics, the range can be extended to C'8 depending on the quality of the strings.
In particular, the inverse distance is expanded using spherical harmonics which are integrated separately to obtain spherical multipole coefficients.
Aristotle uses many guitar techniques which include using a pick, chords, harmonics, effects, as well as hammer ons and pull offs.
However, there is no hard limit to the upper range a virtuoso solo player can achieve using natural and artificial harmonics.
His songs usually incorporate violin and guitar (often using harmonics).
Music using harmonics can contain very high pitch notes difficult or impossible to reach by fretting.
Entwistle's technique ranged from using fingers, plectrum and tapping to using harmonics in his passages.
Using static harmonics and a rock undercurrent, the music was eerie and reflective, at once abstract and grounded by the beat.